As described in U.S. Pat. No. 6,326,177 (Schoenbach et al.), which is incorporated herein by reference in its entirety, a method for intracellular electro-manipulation is described. The method includes applying at least one ultrashort electric field pulse to target cells where the ultrashort electric field pulse has sufficient amplitude and duration to modify subcellular structures in the target cells and does not exceed the breakdown field of the medium containing the target cells. The amplitude and duration of the ultrashort electric field pulse are typically insufficient to substantially alter permeability of the surface membranes of the target cells, e.g., by irreversibly disrupting the cell surface membranes. An apparatus for intracellular electro-manipulation is also provided. The apparatus includes a pulse generator capable of producing an ultrashort electric pulse output and a delivery system capable of directing the electric pulse output to target cells.
However, such devices and methods are insufficient for facilitating treatment of targeted tissue regions, such as tumors. Such devices may thus require multiple treatments exposing the patient to additional risks.
Accordingly, there exists a need for methods and devices which are efficacious and safe in facilitating the treatment of tumors in patients.